From: Alexander Monakov <amonakov@ispras.ru>
Date: Wed, 26 Oct 2022 13:37:34 +0000 (+0300)
Subject: ipa-visibility: remove assert in TLS optimization [PR107353]
X-Git-Tag: basepoints/gcc-14~3698
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=82e629c26647313be406c41a01e6868cfad0f289;p=thirdparty%2Fgcc.git

ipa-visibility: remove assert in TLS optimization [PR107353]

When upgrading TLS access model based on optimized symbol visibility
status, we attempted to assert that recomputing the model would not
weaken it. It turns out that C, C++, and Fortran front-ends all can
(unintentionally) assign a stronger model than what can be derived
from the declaration.

Let's act conservatively instead of asserting, at least as long as
such pre-existing issues remain.

gcc/ChangeLog:

	PR other/107353
	* ipa-visibility.cc (function_and_variable_visibility):
	Conditionally upgrade TLS model instead of asserting.
---

diff --git a/gcc/ipa-visibility.cc b/gcc/ipa-visibility.cc
index 3ed2b7cf6797..238f7eb84d43 100644
--- a/gcc/ipa-visibility.cc
+++ b/gcc/ipa-visibility.cc
@@ -886,8 +886,12 @@ function_and_variable_visibility (bool whole_program)
 	      && vnode->ref_list.referring.length ())
 	    {
 	      enum tls_model new_model = decl_default_tls_model (decl);
-	      gcc_checking_assert (new_model >= decl_tls_model (decl));
-	      set_decl_tls_model (decl, new_model);
+	      STATIC_ASSERT (TLS_MODEL_GLOBAL_DYNAMIC < TLS_MODEL_LOCAL_DYNAMIC);
+	      STATIC_ASSERT (TLS_MODEL_INITIAL_EXEC < TLS_MODEL_LOCAL_EXEC);
+	      /* We'd prefer to assert that recomputed model is not weaker than
+		 what the front-end assigned, but cannot: see PR 107353.  */
+	      if (new_model >= decl_tls_model (decl))
+		set_decl_tls_model (decl, new_model);
 	    }
 	}
     }